Unfortunately, Heroku is no longer free-of-charge. You will need at least their Eco plan, which currently costs $5 USD per month. See their pricing page for more info and up-to-date prices.
If you are a higher-education student, you may be eligible for their student offer, which grants you $13 USD of credits per month for 24 months—enough to host Modmail free for two years.
Fork our GitHub repositories
You will need to fork our repositories to deploy onto Heroku.
Make sure you're logged in to GitHub. You will need to fork two repositories.
Create a GitHub fork for the Logviewer Repository.
Next, to keep your Modmail and Logviewer up to date, you will need to install the Pull app. Simply head over to https://github.com/apps/pull, click Install, choose Only select repositories, then select both the Modmail and Logviewer repositories that you forked in the previous step.